Mid-Term Study Guide: Introduction to Anatomy & Physiology (Ch. 1–15)

1. Introduction to Anatomy

Overview of Anatomy and Physiology

Anatomy and physiology are foundational sciences in understanding the structure and function of the human body. Anatomy focuses on the physical structures, while physiology examines how these structures operate.

• Anatomy: Study of structure.

• Physiology: Study of function.

• Cytology: Study of cells.

• Histology: Study of tissues.

Anatomical Position and Planes

Standard anatomical position and planes are used to describe locations and directions in the body.

• Anatomical position: Body erect, feet flat, palms facing anteriorly, thumbs outward.

• Planes:

  • Sagittal: Divides body into left and right (midline = midsagittal).

  • Frontal (coronal): Divides body into anterior and posterior.

  • Transverse: Divides body into superior and inferior.

Body Cavities and Membranes

Serous membranes line body cavities and cover organs, providing lubrication and protection.

• Serous membranes: Visceral (lines organs) and parietal (lines cavity).

Major Organ Systems

• Urinary system: Regulates ions, pH, produces urine, endocrine functions. Components: Kidneys, ureters, bladder, urethra.

• Respiratory system: Gas exchange between air and blood.

• Muscular system: Locomotion, support, heat production.

• Skeletal system: Bones, joints, cartilages, tendons, ligaments, body framework.

• Diaphragm: Skeletal muscle separating thoracic and abdominopelvic cavities.

2. The Cell

Cell Structure and Function

Cells are the smallest units of life, with specialized structures for various functions.

• Plasma membrane: Phospholipid bilayer controlling transport.

• Diffusion: Facilitated diffusion is passive transport.

• Endocytosis: Pinocytosis and phagocytosis; active processes requiring ATP.

• Exocytosis: Active process for exporting substances; requires ATP.

• Lysosomes: Contain digestive enzymes for pathogens/damaged organelles.

• Osmosis: Diffusion of water across a membrane.

3. Tissue

Types and Functions of Tissues

The body is composed of four primary tissue types, each with distinct functions and structures.

• Epithelial tissue: Covers surfaces, lines cavities, forms glands.

• Connective tissue: Supports, binds, and protects organs.

• Muscle tissue: Produces movement.

• Neural tissue: Includes neurons and neuroglia; responsible for communication.

Stratified Epithelia

• Stratified epithelium: Multiple layers; protection from stress.

• Stratified: Two or more layers.

Neural Tissue Cells

• Neuroglia: Support neurons; types include microglia, oligodendrocytes, Schwann cells, ependymal cells, astrocytes.

• Ependymal cells: Produce cerebrospinal fluid (CSF).

• Microglia: Smallest neuroglia; macrophages of CNS.

4. Integumentary System

Structure and Function of Skin

The integumentary system protects the body and regulates temperature. It consists of the skin, hair, nails, and glands.

• Epidermis layers (thin skin): Basale → spinosum → granulosum → corneum.

• Merkel cells: Located in stratum basale; function as touch receptors.

• Thick skin: Found on palms and soles.

• Dermis: Papillary (loose connective tissue), reticular (dense irregular connective tissue).

• Hair types: Vellus (soft body hair), terminal (thicker, scalp/body).

• Cerumen: Earwax.

• Arrector pili: Smooth muscle attached to hair follicles.

• Sweat glands: Eccrine most widely distributed.

5. Skeletal System

Structure and Function of Bones

The skeletal system provides support, protection, and movement. It consists of axial and appendicular divisions.

• Axial skeleton: Skull, vertebral column, rib cage.

• Appendicular skeleton: Limbs and girdles.

• Red bone marrow: Produces blood cells.

• Yellow marrow: Contains adipocytes (fat cells).

• Osteoblasts: Build bone.

• Osteoclasts: Dissolve matrix, release Ca2+ and phosphate.

Skull and Bone Features

• Lambdoid suture: Between parietal and occipital bones.

• Coronal suture: Between parietal and frontal bones.

• Endochondral ossification: Bone grows in length and diameter.

• Sella turcica: Houses pituitary gland.

• Occipital bone feature: Hypoglossal canal.

• External acoustic meatus: Temporal bone.

• Ethmoid bone: Contains cribriform plate, perpendicular plate, air cells.

• Hyoid bone: Not directly attached to other bones.

• Nasal bone: Articulates with frontal bone.

• Hard palate: Formed by palatine process of maxilla and horizontal plate of palatine bone.

• Vertebral curves: Thoracic and sacral (primary).

• Axis (C2): Has dens.

• Ribs 11 & 12: Floating ribs.

• Mandible: Lower jaw.

• Capitulum: Lower part of humerus.

• Glenohumeral joint: Shoulder joint between scapula and humerus.

• Patella: Largest sesamoid bone.

6. Muscular System

Muscle Structure and Function

The muscular system enables movement, maintains posture, and produces heat. Muscles are organized into connective tissue layers and contract via specialized mechanisms.

• Functions: Movement, support, heat production.

• Connective tissue: Endomysium (fiber), perimysium (fascicle), epimysium (muscle).

• Sarcoplasmic reticulum: Stores calcium ions (similar to smooth ER).

• T-tubules: Spread impulse → Ca2+ release.

• Neurotransmitter: Acetylcholine; Enzyme: Acetylcholinesterase stops contraction.

Major Muscle Groups and Actions

• Mastication: Muscles insert on mandible, innervated by trigeminal nerve.

• Rotator cuff: Supraspinatus, infraspinatus, teres minor, subscapularis.

• Diaphragm: Partition between thoracic and abdominopelvic cavities.

• Hamstrings: Biceps femoris, semimembranosus, semitendinosus.

• Quadriceps femoris: Vastus + rectus femoris, innervated by femoral nerve.

7. Nervous System (Part 1)

Organization and Function

The nervous system coordinates body activities through electrical and chemical signals. It is divided into central and peripheral components.

• CNS: Brain and spinal cord.

• PNS divisions: Afferent (sensory to CNS), efferent (motor out to muscles/glands).

• Effectors: Muscle, gland, specialized cells.

• Autonomic nervous system: Regulates cardiac, smooth muscle, glands.

• Axons from ganglia to effectors: Postganglionic fibers.

• Nodes of Ranvier: Gaps in myelin sheath.

• PNS neuron clusters: Ganglia.

• Convergence: Multiple neurons synapse on one.

• Inferior to lumbosacral enlargement: Spinal cord tapers at conus medullaris.

• Pia mater: Forms denticulate ligaments.

• Subarachnoid space: Contains CSF.

• Motor fibers: Descending tracts of spinal cord.

• Ventral root: Axons of motor neurons.

• Largest nerve: Sciatic nerve (L4–S3).

• Spinothalamic tract: Ascending (sensory).

• Spinothalamic tract final destination: Primary somatosensory cortex.

• Lateral spinothalamic tract: Carries pain and temperature.

• Posterior columns: Carry fine touch, vibration, pressure; integrate in thalamus.

Table: Comparison of Major Tissue Types

Tissue Type	Main Function	Key Cells
Epithelial	Protection, secretion, absorption	Epithelial cells
Connective	Support, binding, transport	Fibroblasts, adipocytes
Muscle	Movement	Muscle fibers
Neural	Communication	Neurons, neuroglia

Key Equations

• Osmosis: $J = -D \frac{dC}{dx}$ (where J is flux, D is diffusion coefficient, C is concentration)

• Facilitated Diffusion: $\text{Rate} = k[\text{Carrier}][\text{Solute}]$